Figure 5.

Late CD169⁺ ablation does not affect T_RM establishment. Wt C57BL/6 and CD169-DTR mice were infected with influenza. (A) Experimental schematic showing DTx regimen began day 10 post-influenza PR8 infection. (B) Representative FACS plots of alveolar macrophages (AM) and inflammatory macrophages (iM) in Wt or CD169 DTR mice (left). Frequency (middle) and cell number (right) of AM, iM, and monocytes (MNC) 22 days post influenza infection in the Lung (top) and BAL fluid (bottom). (C) Representative FACS plots of influenza-specific D^b-NP and D^b-PA tetramer⁺ memory resident (CD45 i.v.–) and circulating (CD45 i.v.+) CD8 T cells in the lung 42 days post-infection. (D) Representative FACS plots of D^b-NP and D^b-PA tetramer⁺ memory. (E) Frequencies of lung CD8 T cells in lung lymphocyte populations in the parenchyma (resident) or circulation (Circ) (top) or of D^b-tetramer positive memory T cells in the CD8 compartments (left) with Numbers of same (right). (F) Numbers of splenic D^b-NP or D^b-PA memory CD8 T cells at day 42 p.i. (G) Frequencies of CD8 T cells from lymphocytes in the spleen (left) or D^b-NP or D^b-PA memory T cells in the CD8 compartment at day 42 p.i. (right). (H) Model indicating the early, but not late presence of resident alveolar macrophages (AM) regulates the CD8 resident memory T cell compartment size without affecting magnitude of effector (CTL) response. Data are representative of three experimental replicates, except (F) which is a single experiment. ^*p < 0.05 for CD169-DTR compared to wt.